---
layout: docs
page_title: AWS KMS seal configuration
description: >-
  Configure Vault sealing to use AWS KMS.
---

# AWS KMS seal configuration

<Note title="Seal wrapping requires Vault Enterprise">

  All Vault versions support **auto-unseal** for AWS, but **seal wrapping**
  requires Vault Enterprise.
  
  Vault Enterprise enables seal wrapping by default, which means the KMS service
  must be available at runtime and not just during the unseal process. Refer to
  the [Seal wrap](/vault/docs/enterprise/sealwrap) overview for more
  information.

</Note>

The AWS KMS seal configures Vault to use AWS KMS as the seal wrapping mechanism.
The AWS KMS seal is activated by one of the following:

- The presence of a `seal "awskms"` block in Vault's configuration file
- The presence of the environment variable `VAULT_SEAL_TYPE` set to `awskms`. If
  enabling via environment variable, all other required values specific to AWS
  KMS (i.e. `VAULT_AWSKMS_SEAL_KEY_ID`) must be also supplied, as well as all
  other AWS-related environment variables that lends to successful
  authentication (i.e. `AWS_ACCESS_KEY_ID`, etc.).

## `awskms` example

This example shows configuring AWS KMS seal through the Vault configuration file
by providing all the required values:

```hcl
seal "awskms" {
  region     = "us-east-1"
  access_key = "AKIAIOSFODNN7EXAMPLE"
  secret_key = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
  kms_key_id = "19ec80b0-dfdd-4d97-8164-c6examplekey"
  endpoint   = "https://vpce-0e1bb1852241f8cc6-pzi0do8n.kms.us-east-1.vpce.amazonaws.com"
}
```

## `awskms` parameters

These parameters apply to the `seal` stanza in the Vault configuration file:

- `region` `(string: "us-east-1")`: The AWS region where the encryption key
  lives. If not provided, may be populated from the `AWS_REGION` or
  `AWS_DEFAULT_REGION` environment variables, from your `~/.aws/config` file,
  or from instance metadata.

- `access_key` `(string: <required>)`: The AWS access key ID to use. May also be
  specified by the `AWS_ACCESS_KEY_ID` environment variable or as part of the
  AWS profile from the AWS CLI or instance profile.  

- `session_token` `(string: "")`: Specifies the AWS session token. This can
  also be provided via the environment variable `AWS_SESSION_TOKEN`.

- `secret_key` `(string: <required>)`: The AWS secret access key to use. May
  also be specified by the `AWS_SECRET_ACCESS_KEY` environment variable or as
  part of the AWS profile from the AWS CLI or instance profile.

- `kms_key_id` `(string: <required>)`: The AWS KMS key ID or ARN to use for encryption
  and decryption. May also be specified by the `VAULT_AWSKMS_SEAL_KEY_ID`
  environment variable.  An alias in the format `alias/key-alias-name` may also be used here.

- `disabled` `(string: "")`: Set this to `true` if Vault is migrating from an auto seal configuration. Otherwise, set to `false`.

- `endpoint` `(string: "")`: The KMS API endpoint to be used to make AWS KMS
  requests. May also be specified by the `AWS_KMS_ENDPOINT` environment
  variable. This is useful, for example, when connecting to KMS over a [VPC
  Endpoint](https://docs.aws.amazon.com/kms/latest/developerguide/kms-vpc-endpoint.html).
  If not set, Vault will use the default API endpoint for your region.

`access_key`, `session_token`, and `secret_key` can be [indirect value references](/vault/docs/configuration/seal#indirect-value-references).

Refer to the [Seal Migration](/vault/docs/concepts/seal#seal-migration) documentation for more information about the seal migration process.

## Authentication

Authentication-related values must be provided, either as environment
variables or as configuration parameters.

~> **Note:** Although the configuration file allows you to pass in
`AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` as part of the seal's parameters, it
is _strongly_ recommended to set these values via environment variables.

AWS authentication values:

- `AWS_REGION` or `AWS_DEFAULT_REGION`
- `AWS_ACCESS_KEY_ID`
- `AWS_SECRET_ACCESS_KEY`

Note: The client uses the official AWS SDK and will use the specified
credentials, environment credentials, shared file credentials, or IAM role/ECS
task credentials in that order, if the above AWS specific values are not
provided.

Vault needs the following permissions on the KMS key:

- `kms:Encrypt`
- `kms:Decrypt`
- `kms:DescribeKey`

These can be granted via IAM permissions on the principal that Vault uses, on
the KMS key policy for the KMS key, or via KMS Grants on the key.

## `awskms` environment variables

Alternatively, the AWS KMS seal can be activated by providing the following
environment variables.

Vault Seal specific values:

- `VAULT_SEAL_TYPE`
- `VAULT_AWSKMS_SEAL_KEY_ID`

## Key rotation

This seal supports rotating the root keys defined in AWS KMS
[doc](https://docs.aws.amazon.com/kms/latest/developerguide/rotate-keys.html). Both automatic
rotation and manual rotation is supported for KMS since the key information is stored with the
encrypted data. Old keys must not be disabled or deleted and are used to decrypt older data.
Any new or updated data will be encrypted with the current key defined in the seal configuration
or set to current under a key alias.

## AWS instance metadata timeout

@include 'aws-imds-timeout.mdx'

## Tutorial

Refer to the [Auto-unseal using AWS KMS](/vault/tutorials/auto-unseal/autounseal-aws-kms)
tutorial to learn how to auto-unseal Vault using AWS KMS.
